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<h2><span class="refentrytitle">Struct template valid_member_type</span></h2>
<p>boost::tti::valid_member_type — A metafunction which checks whether the member 'type' returned from invoking the macro metafunction generated by BOOST_TTI_MEMBER_TYPE ( BOOST_TTI_TRAIT_MEMBER_TYPE ) is a valid type. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../header/boost/tti/member_type_hpp.html" title="Header &lt;boost/tti/member_type.hpp&gt;">boost/tti/member_type.hpp</a>&gt;

</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> BOOST_TTI_TP_T<span class="special">,</span> 
         <span class="keyword">typename</span> BOOST_TTI_TP_MARKER_TYPE <span class="special">=</span> <span class="identifier">BOOST_TTI_NAMESPACE</span><span class="special">::</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">notype</span><span class="special">&gt;</span> 
<span class="keyword">struct</span> <a class="link" href="valid_member_type.html" title="Struct template valid_member_type">valid_member_type</a> <span class="special">:</span> <span class="keyword">public</span> boost::mpl::not_&lt; boost::is_same&lt; BOOST_TTI_TP_T, BOOST_TTI_TP_MARKER_TYPE &gt; &gt;
<span class="special">{</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idm13519"></a><h2>Description</h2>
<p>The metafunction '<a class="link" href="valid_member_type.html" title="Struct template valid_member_type">valid_member_type</a>', which is in the boost::tti namespace, takes the form of:</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">BOOST_TTI_TP_T</span><span class="special">,</span><span class="keyword">class</span> <span class="identifier">BOOST_TTI_TP_MARKER_TYPE</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">tti</span><span class="special">::</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">notype</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">valid_member_type</span>
  <span class="special">{</span>
  <span class="keyword">static</span> <span class="keyword">const</span> <span class="identifier">value</span> <span class="special">=</span> <span class="identifier">unspecified</span><span class="special">;</span>
  <span class="keyword">typedef</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">bool_</span><span class="special">&lt;</span><span class="keyword">true</span><span class="special">-</span><span class="identifier">or</span><span class="special">-</span><span class="keyword">false</span><span class="special">&gt;</span> <span class="identifier">type</span><span class="special">;</span>
  <span class="special">}</span><span class="special">;</span>

<span class="identifier">The</span> <span class="identifier">metafunction</span> <span class="identifier">types</span> <span class="identifier">and</span> <span class="keyword">return</span><span class="special">:</span>

  <span class="identifier">BOOST_TTI_TP_T</span>           <span class="special">=</span> <span class="identifier">returned</span> <span class="identifier">inner</span> <span class="char">'type'</span> <span class="identifier">from</span> <span class="identifier">invoking</span> <span class="identifier">the</span> <span class="identifier">macro</span> <span class="identifier">metafunction</span> <span class="identifier">generated</span> <span class="identifier">by</span> <span class="identifier">BOOST_TTI_MEMBER_TYPE</span> <span class="special">(</span> <span class="identifier">BOOST_TTI_TRAIT_MEMBER_TYPE</span> <span class="special">)</span><span class="special">.</span>
  
  <span class="identifier">BOOST_TTI_TP_MARKER_TYPE</span> <span class="special">=</span> <span class="special">(</span><span class="identifier">optional</span><span class="special">)</span> <span class="identifier">a</span> <span class="identifier">type</span> <span class="identifier">to</span> <span class="identifier">use</span> <span class="identifier">as</span> <span class="identifier">the</span> <span class="identifier">marker</span> <span class="identifier">type</span><span class="special">.</span>
                             <span class="identifier">defaults</span> <span class="identifier">to</span> <span class="identifier">the</span> <span class="identifier">internal</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">tti</span><span class="special">::</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">notype</span><span class="special">.</span>

  <span class="identifier">returns</span>                  <span class="special">=</span> <span class="char">'value'</span> <span class="identifier">is</span> <span class="keyword">true</span> <span class="keyword">if</span> <span class="identifier">the</span> <span class="identifier">type</span> <span class="identifier">is</span> <span class="identifier">valid</span><span class="special">,</span> <span class="identifier">otherwise</span> <span class="char">'value'</span> <span class="identifier">is</span> <span class="keyword">false</span><span class="special">.</span>
                             <span class="identifier">A</span> <span class="identifier">valid</span> <span class="identifier">type</span> <span class="identifier">means</span> <span class="identifier">that</span> <span class="identifier">the</span> <span class="identifier">returned</span> <span class="identifier">inner</span> <span class="char">'type'</span> <span class="identifier">is</span> <span class="identifier">not</span> <span class="identifier">the</span> <span class="identifier">marker</span> <span class="identifier">type</span><span class="special">.</span>
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